单项选择题

薄层色谱采用的Kieselguhr G作为固定相，其组成是（）

A．natural Kieselguhr is added to about 15% of calcium sulphate hemihydrate
B．15% calcium sulphate hemihydrate
C．natural silicone and calcium sulphate
D．aluminium oxide G
E．Cellulose G

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热门试题

单项选择题

英国药典(93年版)规定大黄含羟基葸醌类衍生物，以大黄酸计不得少于2．5%，其英语表示法是（）

A．It contains no less than 2．5% of hydroxyanthracene derivatives,calculated asrhein．
B．It contains down to 2．5% of hydroxyanthracene derivatives,calculated asrhein．
C．It contains more than 2．5% of hydroxyanthracene derivatives,calculated asrhein．
D．It contains up to 2．5% of hydroxyanthracene derivatives,calculated asrhein．
E．It contains not less than 2．5% of hydroxyanthracene derivatives,calculated asrhein．

单项选择题

Identification:Test A may be omitted if test B,and D are carried out．Test B,C,and D may be omitted if test A is carried out．根据上文的规定，假如完成了实验C，如要达到鉴定目的，其他一定要进行的实验是（）

A．TestA
B．TestB
C．TestB和TestA
D．TestA和TestD
E．TestB和TestD